"They were both my kids' dogs so they came home from school and both the dogs were gone... it was a bit sad for them," Samantha Disher said.

Ms Disher said she woke to find Reba lying dead on the grass between her two cars, covered in her faeces, and it appeared she had been vomiting on the Grasstree Road property.

Macey was underneath one of the cars, vomiting, and had diarrhoea. When Ms Disher pulled her out she was "really wobbly and wouldn't walk straight".

She rushed her to the vet but Macey didn't make it.

Ms Disher said her father also lost a cow on his Sarina farm, which he believed was the result of a brown snake bite. Her brother discovered a snake in his house on Sarina Beach Road.

"When he got home there was a massive one in his house and I thought, oh my gosh, I need to warn people, especially kids playing in the backyard," she said.

"A lot of them (the snakes) are hatching as well. Because we haven't had much rain the nests haven't been washed away. The floods normally destroy the nests."

Ms Disher said her brother had posted online about his snake encounter and discovered many other residents were facing the same problem, saying snakes were on the rise.

Northern Beaches veterinarian Paul McGeown said it was the time of year for brown snakes to be out and about.

Mr McGeown said in the past three months Northern Beaches Veterinary Hospital had treated about 30 pets for snake bites, the majority from brown snakes.

He said while the hotspots appeared to be Sarina and Habana, there had been bites in unexpected areas such as Andergrove and Blacks Beach.

Brown snakes are more likely in cane paddocks, places with a lot of rodents or around chickens.

"The best things for keeping snakes away is keeping yards tidy and lawns and weeds under control," Mr McGeown said.

Snake bite symptoms include pets losing the ability to walk, then struggling to breath, then having a hemorrhage. Mr McGeown said the sooner pets were treated, the better the prognosis, depending on the amount of venom injected.